大跨度异型桥动力响应分析

Analysis on Dynamic Response of Long-span Special-shaped Bridge

摘要:

以成都市新都区拟建的1座大跨度人行钢桥为研究背景，通过有限元软件建立全桥三维模型，分析地震荷载和行人荷载下的动力响应，并根据设计规范进行评估。结果显示：在设计地震荷载作用下，桥梁主要构件应力处于弹性状态，塔顶与梁端位移合理，基础受力远低于最大承载能力，显示出优异的抗震性能；在频率为2.313 Hz的行人荷载下，振动加速度数值与其他频率存在较大差异，补充计算发现行人荷载频率为2.474 Hz时振动加速度最大，竖向最大值达到3.361 m/s2；设计并添加调谐质量阻尼器（TMD）后，振动加速度得到有效控制，达到了“最好”的评价指标。

Abstract:

Taking a proposed long-span pedestrian steel bridge in Xindu District of Chengdu as the research background， a three-dimensional model of the whole bridge is established through the finite element software to analyze the dynamic response under seismic and pedestrian loads and evaluate it based on design specifications. The results show that under the design seismic load， the stress in the main components of the bridge is at the elastic state. The displacements at the pylon top and beam ends are reasonable. The foundation stress is far below the maximum bearing capacity. The seismic performance is excellent. Under the pedestrian load with a frequency of 2.313 Hz， the vibration acceleration values significantly differed from those at other frequencies. The supplementary calculations show that the maximum vibration acceleration occurred at the pedestrian load with a frequency of 2.47 Hz， and the vertical maximum is 3.36 m/s2. After a tuned mass damper （TMD) is designed and added， the vibration acceleration is effectively controlled to achieve the “best” evaluation index.